1. Field of the Invention
This invention relates to flexible inspection instruments for use in both industrial and medical applications and, more particularly, to an elongated, flexible, fiber-scopic inspection device with a substantially flexible shaft having a channel means therewith and a deflection compensation means.
2. Prior Art
Elongated tubular inspection devices, particularly such devices incorporating flexible fiber-optics, are often used to inspect sites which would not normally be visible to the human eye. One application of such tubular inspection devices is in the practice of medicine. For instance, a common form of such device, known as a flexible ureteropyeloscope, is used for the inspection of the human ureter and entire kidney area while a similarly structured device, known as a colonoscope, is used for the inspection of the colon.
The ureteropyeloscope is conventionally used for a variety of functions such as observation of areas and presenting a working tool at the area for such things as removing ureteral or kidney stones, dislodgement or electro-hydraulic destruction of ureteral stones, taking biopsies, irradiating tumors with laser fibers, etc. The ureteropyeloscope examination can involve the physician's placing the instrument in the body through the urethra, then into the bladder, then through one of the ureteral tubes and then, if necessary, into the kidney itself. This is usually a time consuming and potentially tortuous path through several organs of the body.
The inspection instrument generally has a control head forming a proximal end and a flexible tubular shaft, the end of which forming a distal end. The physician observes target areas through an eyepiece in the control head. Generally, the ureteropycloscope is provided with a bundle or bundles of optical fibers which bring light to its objective end, the end which is placed adjacent the area to be examined, and a bundle or bundles of light transmitting fibers through which an image of the examined area is transmitted back to the eyepiece. The ureteropyeloscope can generally further incorporate a channel which provides a conduit for providing washing fluid to the site under examination as well as for the introduction of accessory devices to the site such as a biopsy forceps.
The flexible tubular shaft extending between the proximal end and the distal end of the flexible instrument generally has a variety of components passing therethrough. The shaft may have such components as a fiber bundle, a working channel and distal end control wires. The tubular shafts can also have a variety of cross sectional shapes as is seen from U.S. Pats. Nos. 1,958,656; 2,120,996; 3,368,552; 3,792,701 and 3,918,438.
The control head of a flexible ureteropyeloscope is generally capable of serving many purposes including housing the optical eyepiece assembly, providing an entry for a light carrier from a light source, housing a deflection control system for controllably moving the distal end and providing an entry for tools and fluids to enter into the control head and be transported to the objective end by means of the working channel. One such control head is described in co-pending U.S. Patent Application Ser. No. 07/017,813 filed Feb. 24, 1987 entitled "Improved Instrument Control Head" by the same inventor and having the same assignee as the present application, which is incorporated by reference in its entirety herein.
One type of deflectable flexible inspection instrument is described in U.S. Pat. No. 4,530,568 by Haduch et al. entitled "Flexible Optical Inspection System" assigned to the same assignee as herein. In the instrument in that patent, ribs or vertebrae 54 and 55 are used to impart limited flexibility and sufficient rigidity to the instrument to provide a structure which is deflectable. However, use of instruments which require ribs for structural integrity cannot be made with relatively small cross-sectional shafts and therefore have a practical limit on the smallness of their cross-sectional area. In addition, deflectable instruments which use a rib-like frame in their shafts also require protective sheaths around their fiber-optics bundles and control cables which further increases the cross-sectional size of their shafts.
Another type of flexible inspection instrument is shown in U.S. Pat. No. 4,616,631 of Takahashi, which generally has a core of a relatively flexible material also known as a multi-lumen core. The core has straight conduits for housing such things as fiber-optic bundles or allowing the passage of instruments or fluids to the distal end. However, these instruments do not have controllable deflection distal ends because a deflection means contained in the straight conduit of a flexible core has a tendency to involuntarily move the distal end of the instrument during bending of the core or twisting or torquing of the shaft once a target area has been reached.
A problem arises in using presently available inspection instruments in that rib-like framed or multi-sheath framed shafts can often be too large to access target areas through relatively small channels.
A further problem arises in using presently available inspection instruments in that shafts that use flexible cores do not have a deflection means for controllably deflecting the distal end without involuntary movement during bending or torquing of the shaft.
A further problem arises in using presently available inspection instruments in that shafts that use flexible cores do not have a means for compensating for shaft deflection which causes channel means deformation.